Sounds like you might have an anti virus product installed.

But my problem is specific to Thunderbird. If it were an anti-virus issue, wouldn't other apps (e.g., Chrome or other browsers) also be prevented from opening attachments? If so, it's something else...

Test: Start computer in 'Safe mode with networking' Start Thunderbird as normal

test opening attachment report on result.

dtabass,

Did you have this problem PRIOR to Sept 26, when you were using version 52? (not 60)

To finally answer the above: 1. I can't imagine it's a security thing. Attachments open fine if I use the (dreaded) GMail browser interface - e.g., in Chrome or Firefox. It's just Thunderbird where open attempts are a no-op. 2. I tried the safe mode restart; had no effect on the problem. 3. I've been living with the problem for a long time - it started many months ago - I just finally got around to complaining here in the hope that someone has seen the issue and knows the fix. It's really a pain to have to save attachments before looking at them...

Maybe there is some confusion about where to put attachment in order to open it. Try this: Run 'Safari' and access Preferences, then set the default download folder eg: Desktop or Downloads folder.

Start Thunderbird Test opening attachment

Or some confusion about my actual issue.  :-)

In Thunderbird, when I look at attachments in the bottom bar (under the mail content window, see attached image for an example), I should be able to open one by double-clicking on it or by right-clicking on it and picking "open". Neither of those UI actions work. Of course I can download one and then open it, but that's a pain to have to do if I get a message containing an attachment that I'd like to glance at quickly. It's basically just a nuisance that this stopped working somewhere along the way, and I finally got tired enough of working around it to try asking about it here.

What happens when I try to open an attachment in one of those ways is: Nothing. It's a silent no-op. Frustrating!

But have you opened Safari and set Preferences to use eg: Desktop ?

I know this sounds a bit mad, but it would be useful to know that you have just reselected this and what you selected.

I know of two reports

• https://bugzilla.mozilla.org/show_bug.cgi?id=1418444
• https://bugzilla.mozilla.org/show_bug.cgi?id=1506800 for Mac which only started in version 60. Are you seeing this issue from messages you or someone else sent with version 60?

If it is not one of these then it helps to know time frame so I do wish you could be more specific - what does "many months" mean?

Also check tools > error console to see what's there just before and just after you try to open attachment

Question to responder N-1 above: I haven't done anything with Safari because it's not in the picture (I don't use it at all). How would that affect Thunderbird?

Answer to responder N above: I wish I could remember; if I had more of a timetable clue, I would share it. I was too lazy to complain for awhile, then had an IT friend try/fail to fix it in various ways that she thought might work. This was my next step. Meanwhile, it isn't related to the sender - this is a problem for all e-mail attachments of all kinds from all sources. It's only an issue in Thunderbird, as I can open attachments when I am using browser-based mail clients. (Unfortunately I am a big fan of Thunderbird for my e-mail management, so I am hesitant to give it up - and I have a big collection of old e-mail in its format.)

Again, to clarify: This is an issue (just) about VIEWING attachments directly in Thunderbird. Attachments come through fine and thy are perfectly save-able. They just won't OPEN in the way that they are supposed to WITHIN Thunderbird.

OK, let's try multiple choice. It's been happening which of these?

1. Since fall - 3 months
2. Since spring (happening in summer and fall)
3. Since Winter (it was still cold, assuming you are in northern hemisphere)
4. Was happening in 2017

re :Question to responder N-1 above: I haven't done anything with Safari because it's not in the picture (I don't use it at all). How would that affect Thunderbird?

I would not ask you to test this if it was not relevant and needed to be excluded. As I said, I know it sounds a bit mad, but please test this out. Attachments need to be temporarilly saved somewhere in order to open. Safari preferences could be controlling/conflicting with where a document opens.

So please reset Safari preferences to open on Desktop or in Downloads. Then tell the forum where this is set.

Answer to the Safari exception: Just tried it; no change w.r.t. Thunderbird. (But Safari is now putting its downloads in the newly specified location, so I verified that the change was made and took effect.)

Answer w.r.t. timing of the problem: I really don't know, as I tend to work around things for awhile before tackling them. And to make matters worse, I live in SoCal, so it's never really cold; cold is when I need a long-sleeved shirt.  :-) It may be that the problem goes back to my last laptop change, maybe something happened when I went from MacBook Pro n-1 to MacBook Pro n, in terms of Thunderbird.... If that's the case, it would date back to Spring '18. It may be some configuration thing - I was hoping someone would hear/see my problem and recognize its cause.

In Thunderbird > Preferences > Attachments > 'Incoming' tab Save files to: select exactly the same place as you chose in Safari. click on 'OK'

Restart TB, test and post results. Please also post image of Preferences > Attachments > 'Incoming' tab

So everyone understands your current setup: Is this an imap mail account ? If yes: Is the folder which contains the email, selected as synchronised for offline use, so emails are fully downloaded ? Check settings: right click on imap mail account and select 'Settings' select 'Synchronisation & storage'

Is this selected or not ?

• 'Keep messages for this account on this computer'

click on 'Advanced' button Regarding the folder(s) which contains the emails that do not open attachments - are those folders listed and the download checkbox selected ? If folder(s) not selected, please select them. click on all the 'OK's.

If you made any adjustments please restart thunderbird and test image again.

Thanks for your input as it helps to rule in or out what is going on.

Yes to all. I have several accounts attached - all imap - all configured as you said w.r.t. the folder options, and that all seems to work fine. The attachments are there - they just don't open - everything else about my offline/online mail use works without a hitch. The failure to open attachments if orthogonal to where the messages are; it's not specific to a particular folder AFAIK.

YOU NAILED IT! Fixed. Life is good (actually great). What did it was making me look at where attachments were going in Thunderbird with the specific instructions to:

"In Thunderbird > Preferences > Attachments > 'Incoming' tab Save files to:..."

Now I also know exactly what and when things went wrong....

Last May I moved to a new Mac from a backup of an older Mac, and the OS levels were different enough that Apple's automatic restore/reimaging installation software choked. Scary times, as the move was due to a hardware issue on the old Mac. Anyway, in working through that, for reasons not worth explaining here, the Mac support folks ended up guiding me to a workaround that required the creation of a new user identity than my old one, remnants of which still exist on the new Mac. The setting for directing Thunderbird attachments was still pointing to the downloads directory of the OLD account - which the new account didn't have permission to write into - and that directory must be used when opening attachments.... There was even a little red (as in: something's broken) icon that showed up when I looked at the download target path in Thunderbird preferences. I changed the target to be the new account's download directory and all is well with the world again. PHEW.... So - apparently that stopped working as of the machine change - and that's why - there was an old setting in the Thunderbird preferences that were restored into the new account in all of that excitement.

Now it all makes sense..... It was a protections issue. If only there were some way Thunderbird could have communicated that failure to me - rather than just "no-op-ing" the open action - there might be some log somewhere that would have shown that? In any case - fixed!

PS: THANKS AGAIN for sticking it out in this thread and leading me to a happy ending...  :-)

Good to hear all is working again :)